(4) In [1]}, the structure is actually governed by a wave equation. Nevertheless, the same result can be obtained for the plate equation, both for \(\alpha = 0\)  and \(\alpha >0\) , as these cases have more regularity. However, in [2]}, [3]}, \(\alpha >0\)  and the same results cannot be obtained in the same way if \(\alpha =0\) . This is because viscoelasticity ensures maximal regularity [2]} and the analiticity [3]} properties, which play a key role in the respective approaches.

